I am an emergency physician on staff at Lenox Hill Hospital in New York City, where I have practiced for the past 10 years. I also serve as an adviser to Medscape Emergency Medicine, an educational portal for physicians, and an affiliate of WebMD. My other time is spent with my private house call practice called DR 911, providing medical care to both travelers and residents in Manhattan. I have a keen interest in medical technology and public health education.

MERS Update: Incubation Period Longer Than Previously Thought

The novel coronavirus (nCoV), responsible for the newly identified Middle East Respiratory Syndrome (MERS-CoV), belongs to the coronavirus family which is responsible for causing illnesses that range from a common cold to Severe Acute Respiratory Syndrome (SARS). Just until last year, the new strain that is currently circulating in Saudi Arabia had actually never been seen in humans. The novel coronavirus, like SARS, is most closely related to a bat virus.

The World Health Organization (WHO) started tracking the new SARS-like virus globally in September, 2012 and since then, 49 people have had laboratory-confirmed cases, with 5 new cases reported in Saudi Arabia on May 29. So far, with the addition of these 5 new cases, 27 people have died from the virus.

The novel coronavirus originated in Saudi Arabia, and now has spread in the Middle East to places such as Qatar and Jordan. Persons traveling to the Middle East have actually brought the viruses to other countries in Europe including the UK, Germany and France as well as Tunisia.

Prior to the new study reported May 29 in the Lancet, there had been minimal if any transmission of the virus between persons who did not travel in the Middle East, but who were exposed to sick travelers when they returned.

In the first reported case of MERS in France, a 64-year-old French gentleman who had previously traveled to Dubai in early to mid April, died on May 28. It turns out that his hospital roommate also was diagnosed with MERS, but did not have previous travel in the Middle East, evidence that close contact may be a risk factor for spread of the virus.

Now, according to data obtained from these patients, and published online in the Lancet May 29, it appears as though MERS may incubate in patients for a longer duration than doctors previously believed. The bottom line is that patients who are suspected of having MERS may ultimately need to be quarantined or isolated for longer periods to confirm that they are not infected with the virus.

The new study was completed by investigators who visited the two ill French patients, and represents the first in depth clinical review of MERS. It turns out that the hospital roommates shared the same room for three days. The doctors noted that the virus in the second patient had an incubation period of 9- 12 days. The incubation was previously reported to be 1-9 days.

The findings from this study suggest that the incubation period of the virus could potentially reach 9-12 days which ultimately affects the duration of isolation or quarantine for patients with concerning symptoms or a documented exposure to someone with MERS.

The authors of this study conclude that patients returning from the Middle East with respiratory symptoms or with known exposure to a confirmed case of MERS-CoV need to be isolated for at least 12 days, with PCR testing of lower respiratory tract sputum samples for MERS-CoV.

In a wider view, investigators do not really know a great amount of detail about this virus, especially how it mutates after lying dormant in different populations. Ultimately, scientists do not clearly understand how people are getting infected. And, until researchers can truly unlock the mechanism of spread and pathway for infection, they won’t be able to prevent it from spreading.

MERS-CoV does have the ability to spread from person to person. The WHO has reported several so-called clusters in which human-to-human transmission has been confirmed. Transmission could potentially occur by droplet spread, such as coughing or sneezing or by exposure to a contaminated surface or environment.

It turns out that coronaviruses are actually rather fragile, and outside of the body can generally not survive more than 24 hours. The viruses are typically killed by standard cleaning agents and detergents.

All infection control measures to prevent the spread of the virus should be taken for any patient with confirmed illness. This includes isolation of the patient with personal protective equipment with gown, glove and special N-95 masks, along with attention to proper handwashing.

The truth is that if the virus was highly infectious many more cases in other countries or among the people caring for infected patients would likely have been seen by now.

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There have been some early reports associated with MERS-CoV where men were identified (in specific clusters) in greater numbers as developing infection and subsequently dying at a greater rate, even though women were also exposed in at-risk settings. According to early reports, the virus has also infected women whom have subsequently died, though not at the rates observed in men. The difference for the disparity is unclear, and at this time does not definitively indicate a gender preference. The actual numbers of laboratory-confirmed cases is still small, not reflecting those with subclinical or mild infections in the world population at large.

My newborn son’s daycare family went to the Czech Republic for a month. They are due back 7/1/13. How worried should I be that they may have come onto contact with MERs? I am considering waiting 2 weeks to bring him back to them just to be sure. Is that necessary?

Re the gender imbalance – this is almost certainly to do with exposure and men and women are particularly segregated in KSA. Older Saudi men are statistically heavy smokers inhaling deeply and coughing without inhibition – their women tend not to smoke. Saudi SARS has been shown to require receptor cells in the lungs (rather than the membranes of the nose and throat – the upper respiratory tract – which make cold and flu viruses so contagious. There will be an epidemiological explanation for where exactly it is being caught )though some powerful parties may not like it!) Given the even distribution of cases across the KSA it would seem that the virus is already widely distributed hence should pilgrims be allowed to attend the Hajj and not be quarantined on their return home the danger may not be a viral pandemic but that Saudi SARS becomes a lethal endemic virus impossible to eradicate! In a Western country it may kill young people inhaling deeply at a gig or sporting event rather than old men who smoke and their weeping spouses. Certain other factors should be noted; research has shown that this MERS-Cov (2012) virus is the first discovered to be able to grow in the cells of more than one species (rather naively the scientists declared that it was ‘unique’ in this property!) Also coronaviruses are nigh impossible to manufacture acceptable effective vaccines against. Last October whilst the world was distracted by Hurricane Sandy approaching NY and Dr Ian Lipkin was supposed to be monitoring Saudi SARS in the KSA (no report was ever published and autopsies do not seem to have been conducted even on the 30 or so young Egyptian pilgrims who died of respiratory illness) there may have been some Saudis who were misguided enough to fancy that this might be a god-given biological weapon to undermine the hegemony of the West – let us hope that they have now awoken to the likelier outcome that the Saudis will become a pariah nation blamed for seeding their ‘plague’ globally! In terms of a dangerous pandemic influenza is always the front-runner and H1N1 has a few tricks up its sleeve still (despite the WHO ignoring its depredations this year in Northern India). The worst case scenario is probably that H1N1 reassorts with the variant H7N9 inside a pig or child and a highly contagious deadly new virus suddenly appears – moreover on which has the alarming features of H7 viruses: it might not be feasible to make an effective vaccine and which might even have the ghastly H7 characteristic of being able to grow in ocular cells (see how the staff in the Chinese photos are wearing goggles?) Or none of this may happen – viruses are totally unpredictable!